Steve Bannon, the former chief strategist at the White House, described President Donald Trump's firing of former FBI Director James Comey as a historic error.
Charlie Rose asked Bannon, appearing on "60 Minutes" in his first televised interview since departing the Trump administration on Aug. 18, if rumors were true that he had described Comey's firing as the "biggest mistake in political history."
"That probably would be too bombastic, even for me," Bannon said, "but maybe modern political history."
He added that Comey's departure directly spawned the appointment of special counsel Robert Mueller and his investigation into possible collaboration between the Trump administration and Russia to interfere in the 2016 election.
"I don't think there's any doubt that if James Comey had not been fired, we would not have a special counsel," Bannon said. "We would not have the Mueller investigation and the breadth that clearly Mr. Mueller is going for."
Bannon, largely credited with shaping the White House's policy since Trump's inauguration, left the administration last month and returned to Breitbart News, the right-wing website he ran from 2012 until he took a leave of absence in 2016 to join the Trump campaign.
During the interview, Bannon also lambasted the "pearl-clutching mainstream media" and said he is "absolutely" going to war with Republican leaders, whom he said were "trying to nullify the 2016 election."
"They're not gonna help you unless they're put on notice," Bannon said, specifically pointing to Speaker of the House Paul Ryan (R-Wis.) and Senate Majority Leader Mitch McConnell (R-Ky.). "They're gonna be held accountable if they do not support the president of the United States. Right now, there's no accountability."
Earlier on Sunday, Politico reported that Bannon was planning to aid primary challenges against GOP senators who are unsupportive of Trump's agenda.
Bannon, who described himself in the interview as a "street fighter," also said the government needed to "focus on American citizens" when Rose asked about his position on DACA, the Obama-era program that offers some protections to young undocumented immigrants.
Watch the full interview on CBS.